From July 1984 the five Nordic countries (Denmark, Finland, Iceland, Norway and Sweden) have registered all children with acute myeloid leukaemia (AML) and treated them on two consecutive protocols of different intensity (NOPHO-84 and NOPHO-88). We probably have information on every child with this diagnosis in our region. We found an annual incidence of AML of 0.7 new cases per 100,000 children < 16 years of age. We observed a distinct peak of incidence in the first 2 years of life. Children with Down's syndrome accounted for 13% of all cases. Eighty of 105 cases treated on NOPHO-84 achieved remission (78%). In NOPHO-88, 100/118 patients entered remission (85%). The overall event-free survival (p-EFS) for the two studies was 0.32 for NOPHO-84 and 0.42 for NOPHO-88. The majority of relapses occurred within 2 years of diagnosis. When looking for prognostic factors the strongest significant adverse factor found was male sex. Children with Down's syndrome (n = 35) had a very favourable outcome if they received therapy according to protocol, and infants (n = 26) had a superior outcome compared to children 1-2 years or > 10 years of age at diagnosis.

Summary Comparative genomic hybridization (CGH) was used to detect copy number changes of DNA sequences in the Ewing family of tumours (ET). We analysed 20 samples from 17 patients. Fifteen tumours (75%) showed copy number changes. Gains of DNA sequences were much more frequent than losses, the majority of the gains affecting whole chromosomes or whole chromosome arms. Recurrent findings included copy number increases for chromosomes 8 (seven out of 20 samples; 35%), 1q (five samples; 25%) and 12 (five samples; 25%). The minimal common regions of these gains were the whole chromosomes 8 and 12, and 1q21-22. High-level amplifications affected 8q13-24, 1q and 1q21-22, each once. Southern blot analysis of the specimen with high-level amplification at 1q21-22 showed an amplification of FLG and SPRR3, both mapped to this region. All cases with a gain of chromosome 12 simultaneously showed a gain of chromosome 8. Comparison of CGH findings with cytogenetic analysis of the same tumours and previous cytogenetic reports of ET showed, in general, concordant results. In conclusion, our findings confirm that secondary changes, which may have prognostic significance in ET, are trisomy 8, trisomy 12 and a gain of DNA sequences in 1 q.

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